Architecture for open communication in a heterogeneous network

ABSTRACT

Network architecture configured for open communication between a plurality of sub-networks. Each of the plurality of sub-networks has a different routable network addressing scheme. The architecture includes at least one broker node adapted to communicate using at least two different routable network addressing schemes. The broker node comprises an identification management module configured to collect peer-application addresses for nodes currently accessing a specific application, the peer-application addresses being associated with a specific application, an address resolution module configured to map each of the peer-application addresses to a sub-network specific routable network address and a network coordination module configured to monitor and coordinate sub-network communication capabilities between the broker node and at least one other broker node and elect a primary broker node for each sub-network which the broker node and at least one other broker node is capable of communication.

FIELD OF THE INVENTION

This invention relates to architecture which supports open communicationbetween moving vehicles and road-side units or infrastructure where thedifferent vehicles and road-side units may be configured forcommunication in different sub-networks.

BACKGROUND OF THE INVENTION

Wireless communication has become common in all aspects of life today,whether it be a wireless home or office network, so-called “hotspot”networks at local cafes, fast food chains or hotels, or even citywideimplementations of WiFi technologies. This desire to become a society ofwireless communication has even extended to moving devices such as amoving vehicle with the use of mobile networks. This type of wirelessnetworking may appear in many aspects of vehicle safety applications,including, but not limited to, urgent road obstacle warning,intersection coordination, hidden driveway warning, lane-change ormerging assistance. In the mobile networks, different sub-networks areused for communication and grouping vehicles and road-side units (RSUs)such as geographic based sub-networks or peer-group based sub-networks.An local peer group network is described in U.S. Pat. No. 7,848,278issued Dec. 7, 2010 and assigned to Telcordia Technologies, Inc., et al(“Telcordia Tech”), the contents of which is incorporated herein byreference.

However, with the use of different sub-networks, vehicles and RSUsconfigured to communicate in one sub-network cannot communicate withvehicles and RSUs in another sub-network. This is because of theincompatibilities among the different sub-networks such as naming,addressing routing and radio technologies. For example, a geo-basedsource vehicle cannot send a traffic update message to a LPG-basedvehicle.

SUMMARY OF THE INVENTION

Accordingly, disclosed is a mobile communication network configured foropen communication between at least two sub-networks. Each sub-networkhas a different routable network addressing scheme. The networkcomprises a plurality of nodes configured for communicating using afirst sub-network of the at least two sub-networks via a correspondingroutable network addressing scheme, a plurality of nodes configured forcommunicating using a second sub-network of the at least twosub-networks via a corresponding routable network addressing scheme; andat least one broker node configured for communicating using at least twoof the at least two sub-networks via the corresponding routable networkaddressing schemes for each of the sub-networks. The at least one brokernode receives a message from one node of the plurality of nodes of thefirst sub-network of the at least two sub-network and forwards themessage to at least one node in a second sub-network of the at leasttwo-sub-networks based at least upon an application in which the messageis created.

Each broker node broadcasts its status of a broker node to eachsub-network that the broker is configured to communicate. The broadcastis via a broadcast routable address corresponding to each sub-network.

Each broker node maintains a coordinated list of broker nodes and theircorresponding sub-network communication capabilities using informationfrom the broadcast.

Each of the plurality of nodes configured for communicating using thefirst or second sub-networks receives the broadcast and maintains a listof broker nodes.

The application can be an emergency service message. If the applicationis an emergency service message, each broker node broadcasts the messageto each of at least two sub-networks using the broadcast routableaddress corresponding to each of the at least two sub-networks.

Alternatively, the application can be a traffic alert message. If theapplication is a traffic alert message, each broker node broadcasts themessage to each of the at least two sub-networks using the broadcastroutable address corresponding to each of the sub-networks and forwardsthe message to another broker node to distribute the message to othersub-networks that the broker node is not configured for communication.Another broker node is determined based upon the coordinated list ofbroker nodes.

Alternatively, the broker node broadcasts the message to each of the atleast two sub-networks using the broadcast routable addresscorresponding to each of the sub-networks, determines if there is a needto forward the message to another of the at least one broker nodes basedupon a location of a source node and forwards the message to another ofthe at least one broker nodes to distribute the message to othersub-networks that the at least one broker node is not configured forcommunication. Another broker node is determined based upon thecoordinated list of broker nodes and the determined need to forward themessage.

Alternatively, the application generates an unicast packet for anunicast message. The unicast packet can have multiple destinationpoints.

Each broker node receives update messages from each of the plurality ofnodes configured for communicating using the first or secondsub-networks. The update message includes all pending applicationsrunning at each node and a corresponding peer-application address forthe application, sub-network specific routable network address. Eachbroker node stores a pending application identifier, correspondingpeer-application address, peer-application address and sub-networkspecific routable network address for each node. The pending applicationidentifier and corresponding peer-application address is associated witheach other and the peer-application address and the sub-network specificroutable network address is associated with each other.

One node of either of the plurality of nodes configured forcommunicating using the first or second sub-networks broadcasts arequest for a list of peer-application addresses for nodes currentlyaccessing an application. Each broker node responds to the request witha list of peer-application addresses corresponding to the requestedapplication.

A node transmits an unicast packet having the peer-application addressas an application destination and a routable address for a broker nodethat responded to the request with the peer-application address in anetwork header and has a message in a payload.

The broker node that responded to the request with the peer-applicationaddress receives the unicast packet and replaces its routable addresswith a sub-network specific routable network address that corresponds tothe peer-application address in the unicast packet in the network headerand forwards the unicast packet to the application destination.

Also disclosed is a broker node configured for open communicationbetween a plurality of sub-networks. Each of the plurality ofsub-networks has a different routable network addressing scheme. Thebroker node comprises an identification management module configured tocollect peer-application addresses for nodes currently accessing aspecific application, the peer-application addresses being associatedwith a specific application, an address resolution module configured tomap each of the peer-application addresses to a sub-network specificroutable network address; and a network coordination module configuredto monitor and coordinate sub-network communication capabilities betweenthe broker node and at least one other broker node and elect a primarybroker node for each sub-network which the broker node and at least oneother broker node is capable of communication.

The network coordination module is configured to generate a broadcastmessage advertising the broker node's status as a broker node to eachsub-network that the broker is configured to communicate. The broadcastis via a broadcast routable address corresponding to each sub-network.

The network coordination module is configured with a broadcast mutableaddress corresponding to each of the sub-networks. The broadcastroutable address is used when a message is received for a broadcastapplication.

A broadcast application can be, but is not limited to, an emergencyservice message or a traffic alert message.

The routable network addressing scheme for a first of the plurality ofnetworks can be geographic based and routable network addressing schemefor a second of the plurality of networks can be group based.

Alternatively, the routable network addressing scheme for a first of theplurality of networks can be geographic based and the routable networkaddressing scheme for a second of the plurality of networks can beInternet Protocol (IP) based.

The broker node can be, but is not limited to, a moving vehicle orroadside unit.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, benefits, and advantages of the presentinvention will become apparent by reference to the following figures,with like reference numbers referring to like structures across theviews, wherein:

FIG. 1 illustrates an exemplary network having multiple sub-networks;

FIG. 2 illustrates an exemplary open communication network betweenheterogeneous nodes in accordance with the invention;

FIG. 3 is a block diagram of a broker node in accordance with theinvention;

FIG. 4 is a block diagram of an identification management module of abroker node in accordance with the invention;

FIG. 5 is a block diagram of an address resolution module of a brokernode in accordance with the invention;

FIG. 6 is a block diagram of a network coordination module of a brokernode in accordance with the invention; and

FIG. 7 illustrates a block diagram of basic elements of the node adaptedfor communicating in a network according to the invention.

DETAILED DESCRIPTION OF THE INVENTION Definitions

A “Node” is a router that implements the channel determination andselection process or method as specified in the following description.For example, a moving vehicle having a communication device is a node.

A “multicast message” is a message with greater or equal to onedestination. For the purposes of the detailed description a multicastmessage is referenced as a multicast packet (MP).

A “hop” is a number of nodes in which a message is relayed.

A “hop count” between two nodes, i.e., source to a destination, is equalto the number of relay nodes plus 1.

A network can consist of multiple sub-networks (generally references as“15”). FIG. 1 illustrates an example of a network 1 having a pluralityof sub-networks 15. As depicted in FIG. 1 there are six differentsub-networks, e.g., sub-net 1-subnet 6 (15 ₁-15 ₆). A sub-network 15 isa connected set of nodes with a common addressing scheme. Additionally,each sub-network 15 has its own technologies and policies, including butnot limited to, naming, addressing routing and radio technologies. Forexample, the address routing (“routable address”) for a geo-basedsub-network is defined by a location. The routable address for anIP-based sub-network is number IP addresses (class A, B, C, D, E IPaddresses). The routable address for a cellular-based sub-network can bea cellular phone number. The routable address for a LPG-basedsub-network can be a zip code or a vehicle identifier for a LPG groupheader node. RSUs or other infrastructure can have a routable addressusing multiple methods such as, but not limited to, IP addressing,location, etc. Node 10 can be either moving vehicles or road-side units.Additionally, a pedestrian with a wireless communication device can be anode 10. Nodes 10 typically can only communicate using the routableaddress and protocols for one of the sub-networks. For example, Node 110 ₁ communicates using sub-net 1 Geo-based 15 ₁. Typically, a node 10is configured with the protocol(s) for one communication network, i.e.,one network layer. Without open communication, nodes 1-6 10 ₁₋₆ cannotcommunicate with each other.

However, using an open communication network, different user-platforms,e.g., sub-networks 15 are dynamically coordinated into one virtualnetwork. FIG. 2 illustrates a block diagram of an open communicationnetwork 2 according to the invention. Nodes 10 in the open communicationnetwork 2 are divided into two types of nodes: simple nodes (SNs) 200and broker nodes (BNs) 205.

A SN 200 is configured to communicate using one sub-network 15, e.g.,apriori configured with the protocol of one sub-network 15. A SN 200 canhandle only one addressing scheme, e.g., IP. A BN 205 enables messageexchange between different sub-networks and dynamically coordinatedifferent user platforms. As without apriori configurations of all ofthe nodes addresses in the sub-networks 15. A BN 205 is configured withat least two different sub-network protocols, e.g., at least two networklayer protocols. Accordingly, BN 205 supports different address schemes,different routing protocols and different naming. For example, a BN 205can support any and all of sub-net 1-subnet 6 (15 ₁-15 ₆). Any number ofBNs 205 can be used in the open communication network 2 where each BNcan have different sub-network capabilities.

The BNs 205 effectively act as a coordination plane between the SNs 200,e.g., a sub-network plane (individual sub-networks) and an applicationmessage plane (applications). The functions of the BNs 205 areapplication specific. For example, the functionality of a BN 205 for asafety related messages (e.g., broadcast-type of message dissemination)is different than the functionality for a unicast message (point topoint or point to multi-points). The functionality for both will bedescribed in detail later. The coordination plane and BN 205 encompassmultiple protocol layers, i.e., radio, link, network, and application.

A BN 205 actively disseminates or advertises its status as a BN.Additionally, a SN 200 can actively seek a BN 205.

FIG. 3 illustrates a modular block diagram of an exemplary BN 205 inaccordance with the invention. The BN 205 has four modules: anidentification management module 300 (hereinafter “IMM”), an addressresolution module 305 (hereinafter “ARM”), a network coordination module310 (hereinafter “NCM”) and a radio coordination module 315 (hereinafter“RCM”). The BN 205 manages identifications for SNs 200 in theheterogeneous network environment, i.e., identification managementmodule 300, translates the identifications for the SNs 200 intosub-network specific routable addresses, i.e., address resolution module305 and routes and forwards the messages to the sub-network, i.e.,network coordination module 310 and selects a particular radio interface(when multiple radio interfaces are associated with the sub-network) forforwarding the messages, i.e., radio coordination module 315.

FIG. 4 illustrates a block diagram of an IMM 300 according to theinvention. The IMM 300 includes a peer-application address Look-up table(LUT) 400 and a network activity monitoring section 405. Apeer-application address is universal in the open network 2 and is notsub-network specific. A peer-application address is unique identifierfor a SN 200 for a given application. The address is applicationspecific. Additionally, a network application has a unique applicationidentifier. The peer-application address LUT 400 includes a mapping forthe unique application identifiers and the peer-application address forany application that a given SN 200 is currently executing. The networkactivity monitoring section 405 continuously monitors the applicationactivity for SN 200s within its sub-network capability. This is achievedusing the sub-network specific messaging protocol. Each sub-network 15has its own protocols for managing and maintaining the network. The BN205, using the network activity monitoring section 405, can overhearthis information and extract the needed application identifiers andpeer-application address for the current applications running at each SN200.

For example, in an LPG-based sub-network, i.e., sub-net 4 15 ₄, theactivity information can be obtained from a heartbeat control packet ormembership reports, unicast and multicast session information etc. asdescribed in U.S. Pat. No. 7,848,278 issued Dec. 7, 2010 and assigned toTelcordia Tech., the contents of which is incorporated herein byreference.

The IMM 300 is not used for applications that require a broadcastmessage, such as, but not limited to, safety application messages andlocal traffic alerts. However, the IMM 300 is used for applications thatrequire an on-demand unicast, point to point or multipoint message, suchas, but not limited to software and map updates and multi-castapplications.

FIG. 5 illustrates a block diagram of the ARM 305 according to theinvention. The ARM 305 includes a routable address LUT 500 and a messagescope determination section 510. The routable address LUT 500 contains amapping between the peer-application address in the Peer-applicationaddress LUT 400 and a sub-network specific routable address. Thesub-network routable address can be the actual sub-network address ofthe destination node or an address of the next hop to destination node.The next hop to destination node is determined by the local routingtable 630 which will be described later in detail. The routinginformation is based upon the sub-network specific routing protocols.For example, in an LPG-based sub-network, i.e., sub-net 4 15 ₄, thesub-network specific mutable address can be obtained from a heartbeatcontrol packet or membership reports, unicast and multicast sessioninformation etc. as described in U.S. Pat. No. 7,848,278 issued Dec. 7,2010 and assigned to Telcordia Tech., the contents of which isincorporated herein by reference.

The ARM 305 effectively converts a peer-application address from anapplication layer in an incoming message into a sub-network specificroutable address that can be used by the sub-network specific routingprotocol in the BN 205, i.e., NCM 310 and RCM 315.

The message scope determination section 510 determines whether anincoming message needs to be forwarded to another sub-network based upona message scope. The message scope can be application specific. Forexample, a safety application message can be routed to all heterogeneoussub-networks. Alternatively, the location of the source of the safetyapplication message and the location of the BN 205 can be used to limitthe forwarding of the safety application message. A traffic alertmessage can be limited to a specific location. However, a unicast,(point to point or multi-point) message might be routed to a sub-networkbased upon number of hops, current hop count and location. The incomingpacket can include a location of the source, a time to live value forthe packet (maximum hop count) and a relevant location scope.

The ARM 305 is not used for applications that require a broadcastmessage, such as, but not limited to, safety application messages andlocal traffic alerts. However, the ARM 305 is used for applications thatrequire an on-demand unicast, (point to point or multi-point) message,such as, but not limited to software and map updates and multi-castapplications.

FIG. 6 illustrates a block diagram of the NCM 310. The NCM 310 is usedfor coordination of BN activities between multiple BNs 205. The NCM 310interacts with the ARM 305 and the RCM 315.

The NCM 310 includes a broker monitor and transmission section 600, abroker LUT, a broker election section 610 and broker coordinationsection 615. BN advertisements are used by the BNs 205 to inform bothother BNs 205 and SN 200 in the open network 2 of available BN. Theadvertisements are used to track BNs and their capabilities.

The broker monitor and transmission section 600 broadcasts a BNadvertisement. The BN advertisement includes a BN identifier, asub-network specific routable address and a status identifier. Thestatus identifier indicates that the node is a BN 205. The BNadvertisement is broadcast to each sub-network that the BN 205 iscapable of communication, i.e., each sub-network that the BN isconfigured with a protocol for. For example, if the BN 205 has aprotocol for LPG-based address schemes and routing, IP based addressschemes and routing and geographical based address schemes and routing,then the BN 205 will broadcast three separate BN advertisements. Thefirst BN advertisement will include an LPG-based routable address forthe BN, a LPG based name and a BN status identifier. The second BNadvertisement will include an IP routable address for the BN, an IPbased name and a BN status identifier. The third BN advertisement willinclude a geographical based routable address for the BN, a geographicalbased name and a BN status identifier.

The BN advertisement is broadcast using a broadcast routable addressspecific to the sub-network. Each sub-network has a dedicated mutableaddress for broadcasting. The dedicated routable address forbroadcasting for each of the sub-networks which a BN is capable ofcommunicating in is a priori known and stored in a broadcast identifierLUT 620. The broadcast identifier LUT 620 has an entry of broadcastroutable addresses for each sub-network which a BN is capable ofcommunicating. The broadcast routable address is associated with theappropriate sub-network. For example, for an IP-based sub-network,x.y.z.255 can be used. For an LPG-based sub-network, an LPG-ID plus abroadcast specific field such as, but not limited to, “0000” can beused. For a geo-based sub-network, geographical coordinates representinga destination area (broadcast region) instead of a specific coordinatefor a destination point can be used.

The broker LUT 605 includes an entry for each BN 205 in the opencommunication network 2 (including an entry for itself). The entrycontains the name of the BN and the sub-network capabilities (andcorresponding sub-network specific routable address). The name of theother BNs and corresponding capabilities is determined based uponreceipt of the BN advertisement from the other BNs. The brokermonitor/transmission section 600 receives the BN advertisements from theother BNs and extracts the name, routable address and sub-network typeand adds this information into the broker LUT 605. If a BN advertisementis not received from a BN listed in the broker LUT 605, the entry ispurged after a predetermined time. The predetermined time can be afunction of a BN advertisement cycle period. The BN advertisement cycleperiod is the time between two successive BN advertisements.

The broker LUT 605 is used by the broker election section 610 and brokercoordination section 615 to elect and coordinate BN activities betweenmultiple BNs. A BN can be selected to elected based on, but not limitedto, network capabilities, mobility behavior, and their current location.For example, a node with access to a specific location can be elected asa BN to send traffic updates to the specific location.

Depending on the network application message, the broker coordinationsection 615 will aggregate the forwarding of the message with multipleBNs to ensure that the message is forwarded to all availablesub-networks. For example, BN1 is capable of communicating insub-networks 1-3 and BN2 is capable in communicating in sub-networks3-5, BN1 and BN2 will combine their activities to forward the message tosub-networks 1-5. If a traffic alert message is received by BN1, BN1will forward the message to sub-networks 1-3 and forward the message toBN2 to cover sub-networks 3-5. The message will be broadcast using thebroadcast routable addresses for each sub-network in the broadcastidentifier LUT 620 using the broadcast translation section 625. Thebroadcast translation section 625 is used for applications requiringbroadcast messages such as, but not limited to, safety applicationmessages and traffic alert messages. The broadcast identifier LUT 620and broadcast translation section is not used for unicast, (point topoint or multi-point) and multicast application messages.

Local routing table(s) 630 is used to tracking SNs 200 local to the BNs.205. A SN 200 is local to a BN 205 if the node is in a sub-network whichthe BN 205 is capable of communication and within N-number of hops ofthe BN 205. Each local routing table is generated using a correspondingsub-network routing protocol. For example, in an LPG-based sub-network,i.e., sub-net 4 15 ₄, the local routing table 630 is generated from aheartbeat control packet or membership reports, unicast, (point to pointor multi-point) and multicast session information etc. as described inU.S. Pat. No. 7,848,278 issued Dec. 7, 2010 and assigned to TelcordiaTech., the contents of which is incorporated herein by reference.

A data packet (application message) contains a header and contentsection. The header can include an application identifier and apeer-application address. In the case of heterogeneous forwarding, thesub-network specific routable address is for the BN and not that actualend destination. An application layer of the source node generated theapplication packet with the application identifier and peer-applicationaddress. The network layer adds the sub-network specific routableaddress. Additionally, the application layer can add an applicationscope for the application message.

A SN 200 includes a broker LUT. The broker LUT is similar to the brokerLUT 605 in the BN 205 as will not be described again in detail. Forunicast, (point to point or multi-point) applications, the broker LUTcan be used by the SN 200 to obtain a list of available destinations fora given network application. The SN 200 can transmit a request for allpeer-application addresses for a given network application to each ofthe BNs 205 in the LUT. Alternatively, the SN 200 can broadcast the samerequest. Any BNs 205 in the open communication network can respond witha list of peer-application addresses for the requested networkapplication.

Upon receipt of the request, the IMM 300 will respond to the requestwith a list using the peer-application address LUT 400. The request willinclude the application identifier for the requested application. TheIMM 300 will retrieve the peer-application address LUT 400 and read outa list of corresponding peer-application addresses. The BN 205 willtransmit a response to the SN 200. The response will include the list ofpeer-application addresses and a network specific routable address forthe BN.

The application layer at the SN will then generate a unicast, (point topoint or multi-point) application message and append thepeer-application address(es) for the desired destination(s) into theheader along with the application identifier and the content. Thenetwork layer for the SN will add the network specific routable addressfor the BN.

When the BN 205 receives the unicast, (point to point or multi-point)application message, the ARM 305 will translate the peer-applicationaddress(es) into a network specific routable address(es) for thedestination(s) using the routable address LUT 500. The translation willbe performed in conjunction with the local route table 630 in the NCM310. Once the address(es) is/are translated, network specific routableaddress(es) for the destination(s) is/are replaced in the route for theunicast, (point to point or multi-point) application message, i.e., nexthop to destination.

Additionally, the BN 205 can determine if the unicast, (point to pointor multi-point) application message should be forwarded using themessage scope determination section 510 in the ARM 305, i.e., check themessage scope.

For a broadcast application message, such as, but not limited to safetyapplication messages and traffic alert messages, the BN LUT is notneeded. The SN 200 uses the sub-network broadcast address. The BN 205receives the message and broadcasts the message to all of thesub-networks that the BN 205 is capable of communicating in. Dependingon the application, the BN 205 might coordinate with other BNs tobroadcast the application message.

FIG. 7 illustrates a block diagram of basic elements of the node. Thenode includes a memory section 700, a clock 705, a timer 710, atransmission/reception section 715, a control means 720 and a powersource 725. The memory section 700 can be any type of memory includingDRAM, SRAM or Flash. In a preferred embodiment, the short-term memory iscache. The memory section 700 stored the program for causing the controlmeans 720 to execute the functionality of the modules described herein.

The clock 705 is used to maintain the timing for the node. Specifically,the clock 705 functions as an internal clock and is used as a basis forsetting a timer 710. The timer 710 is used to determine when tobroadcast the various messages. The control means 720, e.g.,microprocessor controls all of the processes of the node includinggeneration of the message, routing, timer and executes the functionalityof the modules described herein. Additionally, the control means 720 isalso responsible for header resolution, which will be described later indetail. The transmission and reception section 705 in combination withthe control means 720 is responsible for creating or generating themessage from data, which is stored in the memory section 700.

As will be appreciated by one skilled in the art, the present inventionmay be embodied as a system, method or computer program product.Accordingly, the present invention may take the form of an entirelyhardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as “modules” or “system.”

Various aspects of the present invention may be embodied as a program,software, or computer instructions embodied in a computer or machineusable or readable storage device, which causes the computer or machineto perform the functionality of the modules and disclosed herein whenexecuted on the computer, processor, and/or machine. A program storagedevice readable by a machine, tangibly embodying a program ofinstructions executable by the machine to perform variousfunctionalities and methods described in the present disclosure is alsoprovided.

The system and functionality of the present invention may be implementedand run on a general-purpose computer or special-purpose computersystem. The computer system may be any type of known or will be knownsystems.

The above description provides illustrative examples and it should notbe construed that the present invention is limited to these particularexample. Thus, various changes and modifications may be effected by oneskilled in the art without departing from the spirit or scope of theinvention as defined in the appended claims.

What is claimed is:
 1. A mobile communication network configured foropen communication between at least two sub-networks, where each of theat least one sub-networks has a different routable network addressingscheme, comprising: a plurality of nodes configured for communicatingusing a first sub-network of the at least two sub-networks via acorresponding routable network addressing scheme; a plurality of nodesconfigured for communicating using a second sub-network of the at leasttwo sub-networks via a corresponding routable network addressing scheme;and at least one broker node configured for communicating using at leasttwo of the at least two sub-network via the corresponding routablenetwork addressing schemes for each of the sub-networks, the at leastone broker node receives a message from one node of the plurality ofnodes of the first sub-network of the at least two sub-network andforwards the message to at least one node in a second sub-network of theat least two-sub-networks based at least upon an application in whichthe message is created; each of the at least one broker node receivesupdate messages from each of the plurality of nodes configured forcommunicating using the first or second sub-networks, the updatemessages including all pending applications running at each node and acorresponding peer-application address for the application, sub-networkspecific routable network address and stores a pending applicationidentifier, corresponding peer-application address, peer-applicationaddress and sub-network specific routable network address for each node,the pending application identifier and corresponding peer-applicationaddress is associated with each other and the peer-application addressand the sub-network specific routable network address is associated witheach other; wherein each of the plurality of nodes configured forcommunicating using the first or second sub-networks receives thebroadcast and maintains a list of broker nodes; and wherein theapplication generates an unicast packet for an unicast message.
 2. Themobile communication network according to claim 1, wherein one node ofeither of the plurality of nodes configured for communicating using thefirst or second sub-networks broadcasts a request for a list ofpeer-application addresses for nodes currently accessing an application,each of the at least one broker nodes responds to the request with alist of peer-application addresses corresponding to the requestedapplication.
 3. The mobile communication network according to claim 2,wherein the one node either of the plurality of nodes configured forcommunicating using the first or second sub-networks transmits anunicast packet having the peer-application address as an applicationdestination and a routable address for a broker node that responded tothe request with the peer-application address in a network header andhas a message in a payload.
 4. The mobile communication networkaccording to claim 3, wherein the broker node that responded to therequest with the peer-application address receives the unicast packetand replaces its routable address with a sub-network specific routablenetwork address that corresponds to the peer-application address in theunicast packet in the network header and forwards the unicast packet tothe application destination.
 5. The mobile communication networkaccording to claim 4, wherein the unicast packet has multipledestination points.